Understanding the functional role of neuromodulation for sensory processing is a crucial step in understanding the impact of neurodegenerative diseases affecting neuromodulatory centers in the brain on sensory processing. The overall goal of this project is to further our understanding of the functional role of acetylcholine in olfactory sensation by recording from the neuromodulatory neurons projecting to the olfactory system during olfactory behaviors. I propose to characterize during which parts of olfactory sensation neurons emitting acetylcholine (ACh) to the olfactory system are activated. Together with data already collected on how the blockade of these substances locally in the OB affects olfactory behaviors, these data will be crucial to a more complete understanding of neuromodulatory function in the OB. These data should provide important insights into how neurodegenerative diseases affect olfactory sensation. [unreadable] [unreadable] [unreadable]